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/**
* @file src/mos.c MOS (Mean Opinion Score)
*
* Copyright (C) 2010 - 2016 Creytiv.com
*/
#include <re.h>
#include <baresip.h>
#include "core.h"
static double rfactor_to_mos(double r)
{
double mos;
mos = 1 + (0.035) * (r) + (0.000007) * (r) * ((r) - 60) * (100 - (r));
if (mos > 5)
mos = 5;
return mos;
}
/**
* Calculate Pseudo-MOS (Mean Opinion Score)
*
* @param r_factor Pointer to where R-factor is written (optional)
* @param rtt Average roundtrip time
* @param jitter Jitter
* @param num_packets_lost Number of packets lost
*
* @return The calculated MOS value from 1 to 5
*
* Reference: https://metacpan.org/pod/Algorithm::MOS
*/
double mos_calculate(double *r_factor, double rtt,
double jitter, uint32_t num_packets_lost)
{
double effective_latency = rtt + (jitter * 2) + 10;
double mos_val;
double r;
if (effective_latency < 160) {
r = 93.2 - (effective_latency / 40);
}
else {
r = 93.2 - (effective_latency - 120) / 10;
}
r = r - (num_packets_lost * 2.5);
if (r > 100)
r = 100;
else if (r < 0)
r = 0;
mos_val = rfactor_to_mos(r);
if (r_factor)
*r_factor = r;
return mos_val;
}
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